Chest wall volumes during inspiratory loaded breathing in COPD patients.

Chest wall volumes and breathing patterns of 13 male COPD patients were evaluated at rest and during inspiratory loaded breathing (ILB). The sternocleidomastoid (SMM) and abdominal muscle activity was also evaluated. The main compartment responsible for the tidal volume at rest and during ILB was the abdomen. During ILB patients exhibited, in addition to increases in the ratio of inspiratory time to total time of the respiratory cycle and minute ventilation, increases (p<0.05) in the chest wall tidal volume by an increase in abdomen tidal volume as a result of improvement of end chest wall inspiratory volume without changing on end chest wall expiratory volume. The SMM and abdominal muscle activity increased 63.84% and 1.94% during ILB. Overall, to overcome the load imposed by ILB, COPD patients improve the tidal volume by changing the inspiratory chest wall volume without modifying the predominant mobility of the abdomen at rest and without affecting the end chest wall expiratory volume.